Field of Invention
The present invention relates to a power divider in an electronic circuit, and particularly to a broadband multilayered power divider and a method of fabricating the same.
Description of Prior Art
Power dividers have very wide applications in antenna feedings, balanced amplifiers, mixers and phase shifters. Wilkinson power divider proposed in reference document [1] (R. J. Wilkinson, “An N-way hybrid power divider,” IEEE Trans. Microw. Theory Tech., vol. MTT-8, no. 1, pp. 116-118, January 1960) has completely matched output ports with sufficiently high isolation. Moreover, it offers equal-phase characteristics at each of its output ports. However, conventional Wilkinson power divider with quarter-wavelength branches has a narrow fractional bandwidth less than 20%, which limits its broadband applications. Approaches using lumped elements (referring to reference documents [2] T. Kawai, H. Mizuno, I. Ohta and A. Enokihara, “Lumped-element quadrature Wilkinson power divider,” Proc. IEEE Asia-Pacific MIcrow. Conf., pp. 1012-1015, December 2009; [3] M. M. Elsbury, P. D. Dresselhaus, S. P. Benz and Z. Popovic, “Integrated broadband lumped-element symmetrical-hybrid N-way power dividers,” IEEE MTT-S Int. Microw Symp. Dig., pp. 997-1000, 2009; and [4] S.-H. Cho, C. H. Park, I.-Y. Chung and J. Jeong, “Wideband impedance-transforming three-port power divider using lumped elements,” Microw. Opt. Tech. lett., vol. 51, no. 11, pp. 2570-2573, 2009), open stubs (referring to reference documents [5] S. W. Wong and L. Zhu, “Ultra-wideband power divider with good in-band splitting and isolation performances,” IEEE Microw. Wireless Compon. Lett., vol. 18, no. 8, pp. 518-520, August 2008 and [6] 0. Ahmed and A. R. Sebak, “A modified Wilkinson power divider/combiner for ultrawideband communications,” Proc. IEEE Antennas and Propagation Int.l Symp., 2009, pp. 1-4) and coupled lines (referring to reference documents [7] A. M. Abbosh, “A compact UWB three-way power divider,” IEEE Microw. Wireless Compon. Left., vol. 17, no. 8, pp. 598-600, August 2007 and [8] A. M. Abbosh, “Ultra wideband inphase power divider for multilayer technology,” IET Microw. Antennas Propag., vol. 3, iss. 1, pp. 148-153, 2009) have been proposed to enhance bandwidth. Cascaded multi-stage Wilkinson power divider proposed in reference document [9] (S. B. Cohn, “A class of broadband three port TEM-mode hybrid,” IEEE Trans. Microw. Theory Tech., vol. MTT-16, no. 2, pp. 110-116, February 1968) has considerably increased bandwidth and isolation between output ports, but it occupies very large circuit size due to its planar multi-stage structure, as shown in FIG. 1.
Thus, there is a desire for a broadband and miniaturized power divider.